KVM: PPC: Book3S: Add kernel emulation for the XICS interrupt controller

This adds in-kernel emulation of the XICS (eXternal Interrupt
Controller Specification) interrupt controller specified by PAPR, for
both HV and PR KVM guests.

The XICS emulation supports up to 1048560 interrupt sources.
Interrupt source numbers below 16 are reserved; 0 is used to mean no
interrupt and 2 is used for IPIs.  Internally these are represented in
blocks of 1024, called ICS (interrupt controller source) entities, but
that is not visible to userspace.

Each vcpu gets one ICP (interrupt controller presentation) entity,
used to store the per-vcpu state such as vcpu priority, pending
interrupt state, IPI request, etc.

This does not include any API or any way to connect vcpus to their
ICP state; that will be added in later patches.

This is based on an initial implementation by Michael Ellerman
<michael@ellerman.id.au> reworked by Benjamin Herrenschmidt and
Paul Mackerras.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
[agraf: fix typo, add dependency on !KVM_MPIC]
Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 53 insertions, 1 deletions

diff --git a/arch/powerpc/kvm/book3s_rtas.c b/arch/powerpc/kvm/book3s_rtas.c
index 6ad7050eb67d..77f9aa5f4ba5 100644
--- a/arch/powerpc/kvm/book3s_rtas.c
+++ b/arch/powerpc/kvm/book3s_rtas.c
@@ -17,13 +17,65 @@
 #include <asm/hvcall.h>
 #include <asm/rtas.h>
 
+#ifdef CONFIG_KVM_XICS
+static void kvm_rtas_set_xive(struct kvm_vcpu *vcpu, struct rtas_args *args)
+{
+        u32 irq, server, priority;
+        int rc;
+
+        if (args->nargs != 3 || args->nret != 1) {
+                rc = -3;
+                goto out;
+        }
+
+        irq = args->args[0];
+        server = args->args[1];
+        priority = args->args[2];
+
+        rc = kvmppc_xics_set_xive(vcpu->kvm, irq, server, priority);
+        if (rc)
+                rc = -3;
+out:
+        args->rets[0] = rc;
+}
+
+static void kvm_rtas_get_xive(struct kvm_vcpu *vcpu, struct rtas_args *args)
+{
+        u32 irq, server, priority;
+        int rc;
+
+        if (args->nargs != 1 || args->nret != 3) {
+                rc = -3;
+                goto out;
+        }
+
+        irq = args->args[0];
+
+        server = priority = 0;
+        rc = kvmppc_xics_get_xive(vcpu->kvm, irq, &server, &priority);
+        if (rc) {
+                rc = -3;
+                goto out;
+        }
+
+        args->rets[1] = server;
+        args->rets[2] = priority;
+out:
+        args->rets[0] = rc;
+}
+#endif /* CONFIG_KVM_XICS */
 
 struct rtas_handler {
         void (*handler)(struct kvm_vcpu *vcpu, struct rtas_args *args);
         char *name;
 };
 
-static struct rtas_handler rtas_handlers[] = { };
+static struct rtas_handler rtas_handlers[] = {
+#ifdef CONFIG_KVM_XICS
+        { .name = "ibm,set-xive", .handler = kvm_rtas_set_xive },
+        { .name = "ibm,get-xive", .handler = kvm_rtas_get_xive },
+#endif
+};
 
 struct rtas_token_definition {
         struct list_head list;